Tapered wall radome

Patent metadata

Field	Value
Publication number	US-11658406-B2
Application number	US-201916444520-A
Country	US
Kind code	B2
Filing date	Jun 18, 2019
Priority date	Jun 18, 2019
Publication date	May 23, 2023
Grant date	May 23, 2023

Abstract

In examples, systems and methods for direction finding of electromagnetic signals are described. The device includes a first antenna configured to receive electromagnetic energy. The device also includes a second antenna configured to separately receive the same electromagnetic energy. The device further includes a radome located in a receiving pathway of the first antenna, where the radome is configured to cause a predetermined phase shift that varies based on an angular position of the receiving pathway. The device includes 1 or more radio receivers to receive the signals independently from the antennas. Additionally, the direction finding device includes a processor configured to determine an angle of arrival of the electromagnetic energy based on a comparison of a phase of the electromagnetic energy received by the first antenna to a phase of the electromagnetic energy received by the second antenna.

First claim

What is claimed is:

1. A direction-finding device comprising:
a first antenna configured to receive first electromagnetic energy;
a second antenna configured to receive second electromagnetic energy;
a radome positioned to cover and protect the first antenna such that the radome is located in a receiving pathway of the first antenna, wherein the radome is configured to cause a predetermined phase shift to the first electromagnetic energy received by the first antenna, wherein the predetermined phase shift varies based on an angular position of the receiving pathway of the first antenna, and wherein the radome is not located in a receiving pathway of the second antenna;
a motor coupled to the radome and configured to rotate the radome relative to the first antenna; and
a radio receiver configured to receive the first electromagnetic energy from the first antenna and second electromagnetic energy from the second antenna, wherein the radome causes a phase of the first electromagnetic energy to differ from a phase of the second electromagnetic energy.

2. The direction-finding device of claim 1 , further comprising a processor configured to determine an angle of arrival of the electromagnetic energy based on a comparison of the phase of the first electromagnetic energy received by the first antenna to the phase of the second electromagnetic energy received by the second antenna.

3. The direction-finding device of claim 1 , wherein the first antenna and the second antenna have the same geometry.

4. The direction-finding device of claim 3 , wherein the first antenna and the second antenna are bi-conical antennas.

5. The direction-finding device of claim 1 , wherein a phase center of the first antenna is located a distance approximately equal to one-quarter of a wavelength of a frequency of operation from a phase center of the second antenna.

6. The direction-finding device of claim 1 , wherein the radome has a tapered wall thickness.

7. The direction-finding device of claim 1 , wherein the radome has a permittivity that varies based on a position on the radome.

8. The direction-finding device of claim 1 , wherein the permittivity is based on one of a printed pattern on the radome or a plurality of segments forming the radome, and wherein each segment has a respective permittivity.

9. The direction-finding device of claim 1 , wherein the first electromagnetic energy and the second electromagnetic energy have a frequency between 8 gigahertz and 12 gigahertz.

10. A method comprising:
receiving first electromagnetic energy by a first antenna, wherein the first electromagnetic energy passes through a radome before being received by the first antenna, and wherein the radome is positioned to cover and protect the first antenna, and wherein the radome causes a predetermined phase shift to the first electromagnetic energy received by the first antenna, wherein the predetermined phase shift varies based on an angular position of a received pathway of the first antenna; and
separately receiving second electromagnetic energy by a second antenna, wherein the radome is not located in a receiving pathway of the second antenna;
wherein the radome is coupled to a motor configured to rotate the radome relative to the first antenna, and wherein the radome causes a phase of the first electromagnetic energy to differ from a phase of the second electromagnetic energy.

11. The method of claim 10 , further comprising determining an angle of arrival of the first electromagnetic energy, by a processor, based on a comparison of the phase of the first electromagnetic energy received by the first antenna and the phase of the second electromagnetic energy received by the second antenna.

12. The method of claim 10 , wherein the first antenna and the second antenna have the same geometry.

13. The method of claim 11 , wherein said receiving the first electromagnetic energy by the first antenna is at a location at a distance equal to one-quarter of a wavelength of a frequency of operation from said receiving the second electromagnetic energy by the second antenna.

14. The method of claim 10 , further comprising causing the phase shift by using a tapered wall thickness of the radome.

15. The method of claim 10 , further comprising causing the phase shift by using a permittivity of the radome that varies based on a position of the radome.

16. The method of claim 10 , further comprising providing one of a printed pattern on the radome or a plurality of segments forming the radome, wherein each segment has a respective permittivity.

17. The method of claim 10 , further comprising rotating the radome by using the motor.

18. The method of claim 10 , wherein the received first electromagnetic energy and the received second electromagnetic energy have a frequency between 8 gigahertz and 12 gigahertz.

19. A direction-finding device comprising:
a first bi-conical antenna configured to receive first electromagnetic energy;
a second bi-conical antenna configured to separately receive second electromagnetic energy, wherein:
the second bi-conical antenna has the same geometry as the first bi-conical antenna;
a phase center of the first bi-conical antenna is located one-quarter of a wavelength of a frequency of operation from a phase center of the second bi-conical antenna; and

a radome positioned to cover and protect the first bi-conical antenna such that the radome is located in a receiving pathway of the first bi-conical antenna, wherein the radome is configured to cause a predetermined phase shift to the first electromagnetic energy received by the first bi-conical antenna, wherein the predetermined phase shift varies based on an angular position of the receiving pathway of the first bi-conical antenna, and wherein the radome is not located in a receiving pathway of the second bi-conical antenna;
a motor coupled to the radome and configured to rotate the radome relative to the first bi-conical antenna; and
a processor configured to determine an angle of arrival of the first electromagnetic energy based on a comparison of a phase of the first electromagnetic energy received by the first bi-conical antenna and a phase of the second electromagnetic energy received by the second bi-conical antenna.

20. The direction-finding device of claim 1 , further comprising:
a processor configured to provide a signal to the motor, wherein the motor is configured to rotate the radome based on receiving the signal from the processor.

Assignees

• Boeing Co

Inventors

• Lavin Ronald O
• Lore Michael M
• Lee Andy H
• Carr Michael B

Classifications

• G01S3/12

  Means for determining sense of direction, e.g. by combining signals from directional antenna or goniometer search coil with those from non-directional antenna (determining direction by amplitude comparison of signals derived by combining directional and non-directional signals G01S3/24, G01S3/34) · CPC title

• H01Q1/28

  Adaptation for use in or on aircraft, missiles, satellites, or balloons · CPC title

• H01Q1/225

  used in level-measurement devices, e.g. for level gauge measurement · CPC title

• G01S3/04

  Details · CPC title

• H01Q21/24

  Combinations of antenna units polarised in different directions for transmitting or receiving circularly and elliptically polarised waves or waves linearly polarised in any direction {(circularly polarised patch antennas H01Q9/0428; circularly polarised horns H01Q13/0241; cross-polarised horns H01Q13/0258; polarisation converters H01Q15/242; cross-polarised rear feeds H01Q19/136; crossed polarisation dual antenna H01Q25/001)} · CPC title